Apple PowerBook Duo Dock (including Duo Dock Plus) - Manual (Page 31)

5 Click Customize, or if you have System 7.5, choose Custom Install from the pop-up
menu.
You see the Customize dialog box. (If you have System 7.5, this dialog box
looks slightly different.)
6 Click the EtherTalk item to select it. (You may need to scroll through the list to find
EtherTalk.)
Information about the item you select appears in the box.
7 Click Install.
The Installer begins to install networking software on your PowerBook Duo.
8 Follow the instructions that appear on screen.
If a disk is ejected and you see a message instructing you to insert another
system software disk, insert the specified disk.
9 When you see a message that the installation was successful, click Quit to quit the
Installer program.
If a message reports that installation was not successful, follow the
instructions on screen to try installing again.
10 Click Restart in the dialog box that appears when you quit the Installer.
The PowerBook Duo restarts with the new networking software installed.
25 Using Your Duo Dock on an EtherTalk Network